The novel was also published in the U.S. under the title The Insidious Dr. Fu-Manchu and was adapted into the film The Mysterious Dr. Fu Manchu.

Dr. Petrie is surprised by a late night visitor, "a tall, lean ... square cut ... sun baked" man who turns out to be his good friend (ex-Assistant Commissioner Sir Denis) Nayland Smith of Burma, formerly of Scotland Yard, who has come directly from Burma.

Fu Manchu is pursued from the opium dens of Limehouse in the East End of London to various country estates.

Nayland Smith is outwitted several times by Fu Manchu and thus he reflects more the narrow escapes of the later Bulldog Drummond rather than the "logical" superior approach of the earlier Sherlock Holmes.

Fu Manchu is a master poisoner and chemist, a cunning member of the Yellow Peril, "the greatest genius which the powers of evil have put on the earth for centuries", though his mission is not exactly clear at this stage.